An RFID sensor comprises an RFID chip, an antenna, and sensing material. The RFID chip is in electrical communication with the antenna and comprises an optical sensor. The sensing material overlies an upper surface of the RFID chip and is configured as a variable light filter that filters light differently depending upon certain properties or conditions of the environment surrounding the RFID sensor. A light source is configured to selectively illuminate the sensing material to facilitate detection of certain properties or conditions of the environment surrounding the RFID sensor.
Legal claims defining the scope of protection, as filed with the USPTO.
1. A method for detecting properties or conditions of an environment comprising: overlaying a sensing material onto a surface of a first RFID chip having a structure to form a RFID sensor, configuring the first RFID chip to function as an optical sensor; introducing a second RFID chip that has an inert material and the second RFID chip is part of the structure of the first chip; configuring the sensing material to function as a variable light filter that filters light differently depending upon the properties or conditions of the environment surrounding the RFID sensor; directing light from a light source towards the RFID sensor and the second chip and the light source is selectively operated by an RFID reader wherein the RFID reader periodically activates the light source to monitor the change in a condition or parameter over time and an amount of light permitted through to the sensing material is a function of a presence or concentration of the sensed condition or parameter; and detecting the response of the RFID sensor and looking at the difference between a response from each of the first and second chip in response to the light.
2. The method of claim 1 , wherein the second RFID chip has the same sensing material isolated from the environment.
3. The method of claim 1 , wherein the light source can remain on during the operation of the RFID reader.
4. The method of claim 1 , further comprising determining the magnitude of the presence or concentration of the sensed condition or parameter based at least in part on a comparison of the difference between a response from each of the first RFID chip and the second RFID chip.
5. The method of claim 1 , where the condition or parameter is at least one of the group including humidity, temperature, atmospheric pressure, and pH.
6. The method of claim 1 , where the properties or conditions of the environment surrounding the RFID sensor alter or modify the sensing material.
7. The method of claim 1 , where the configuring step comprises configuring the sensing material to function as a variable near-infrared light filter that changes at least one of its color or opacity in response to the sensed condition or parameter.
8. The method of claim 1 , where the light source is selectively operated by the RFID reader based upon the communication status between the RFID reader and the RFID sensor.
9. The method of claim 1 , where an opacity of the sensing material varies in response to a change in the presence or concentration of the sensed condition or parameter.
10. The method of claim 9 , where the higher the presence or concentration of the sensed condition or parameter, the less light is allowed to pass through the sensing material.
11. The method of claim 1 , where a reflectivity of the sensing material varies in response to a change in the presence or concentration of the sensed condition or parameter.
12. The method of claim 1 , where an absorption of the sensing material varies in response to a change in the presence or concentration of the sensed condition or parameter.
13. The method of claim 1 , where a refractivity of the sensing material varies in response to a change in the presence or concentration of the sensed condition or parameter.
14. The method of claim 1 , where a color of the sensing material varies in response to a change in the presence or concentration of the sensed condition or parameter.
15. The method of claim 14 , where the sensing material comprises a thermochromic material that changes color in response to heat.
16. The method of claim 14 , where the sensing material comprises a biomimetic sensor that darkens in the presence of carbon monoxide.
17. The method of claim 14 , where the sensing material comprises one of a titanium oxide compound or a palladium oxide compound that changes color in the presence of hydrogen gas.
18. The method of claim 1 , further comprising attaching the RFID sensor to a shipping container to monitor for levels of relative humidity.
19. The method of claim 1 , where the condition or parameter comprises one or more bio-hazardous materials.
20. The method of claim 19 , further comprising providing the RFID sensor as part of a public transportation system to monitor for levels of the one or more bio-hazardous materials.
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March 15, 2013
September 17, 2019
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